Chair iron



Jan. 14, 1941. H. w. BOLENS CHAIR IRON Filed April 10, 1937 2 Sheets-Sheet 1 INVENTOR- HARRY W. BOLENS ATTORNEY H. W. BOLENS Jan. '14, 1941.

CHAIR IRON 2 Sheets-Sheet 2 Filed April 10, 1937 t 2 NM 8 3 mm Nu ON kw Nu nv ON .wm mm w mm mix N ON .8 mm .m m

w m a R E Wm m m m B 3 V W ,M m m m A H m Q ATTORNEY Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE 6 Claims.

This invention relates in general to office chairs or swivel chairs which permit the user of the chair to turn with ease and comfort and also to tilt the chair backwardly with a smooth cushioned movement and without strain or danger.

One of the objects of the invention is to provide a chair of this character wherein the yielding resistance to the backward tilting of the chair is developed in an elastic body such as a rubber sleeve or block which is so constructed and organized with the other elements of the chair iron as to present first a slight and then a gradually increasing resistance to backward tilting movement.

Another object of the invention is to provide a chair of this character wherein the yielding resistance to backward tilting is had. without squeaks or noise and without danger of breakage of parts and while presenting a structure which will not collect dust.

A further object is to provide a chair of this character and having these advantages and which is simple and durable in its construction, reliable and effective in operation, and easy and inexpensive to manufacture.

Other objects and advantages reside in certain novel features of the construction, arrangement and combination of parts which will be hereinafter more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings and in which:

Figure 1 is a view in elevation showing an oflice chair embodying the present invention;

Figure 2 is a fragmentary View through the seat and chair iron illustrating the parts in central vertical longitudinal section in some instances and in side elevation in others;

Figure 3 is a view in horizontal section taken on line 3-3 of Figure 2, parts being broken away and showing a section for the sake of illustration; and

Figure 4 is a fragmentary view in vertical section taken on line 4-4 of Figure 2.

Referring to the drawings and more particularly to Figure 1 it will be seen that the chair there illustrated is shown as comprising generally a base I having legs 2 provided with casters or rollers 3. The seat 4 of the chair is supported on the base I by means of a chair iron designated generally at 5 and embodying the present invention. As usual, the chair may be provided with a back 8-and arms 1.

The chair iron comprises the usual spindle l0, accommodated in a bushing I I provided therefor in the base I. A nut 12 is threaded on the spindle and engages the flanged upper end of the bushing II to determine the vertical adjustment of the seat of thechair. Ball bearings may be provided between the nut l2 and the flanged upper end of 5;; the bushing H. The nut I2 may be equipped with the usual cap l3.

A head I5 is fixed to and supported on the upper end of the spindle Ill. This head I5 is usually a casting of suitable design. A spider r; designated'generally at I6 is pivotally mounted on the head Hi. This spider l6 has a pair of transversely spaced longitudinally extending spider arms I! the ends of which are apertured to adapt them to be secured as by means of screws 1 I8 to the under side of the seat 4 of the chair. Intermediate their ends, the arms I! of the spider are interconnected by means of a sheet metal yoke or frame designated generally at I9. This yoke H! has side members vertically disposed 2p and parallel to each other. The side members 20 are riveted as at 2| or otherwise suitably secured to the spider arms IT. The upper edges of the side members 20 are integral with the top cross plate 22. The rear ends of the side members are integral with a vertical cross member 23. While the particular yoke shown is described as of one piece construction, it may, of course, be constituted of separate pieces suitably connected together.

In the assembly the lower portion of the side members 20 overlap transversely spaced bearings 25 provided on the head'casting l5. A pivot pin 26 is supported in these bearing members 25 and has its ends projecting there beyondand through bronze bushings 21' fitted in pivot openings 21. provided in the lower portions of the side members 20 of the yoke. The bushings 21 provide noiseless bearings which do not require lubrication. The ends of the-pivot pin 28 may be peaned 449 over or headed as at 26' to prevent axial displacement of the pin. In this way the spider and the chair seat fastened thereto are supported for pivotal movement with respect to the head l5 of the chair iron and this in such manner as to allow backward tilting of the chair.

The extent to which the chair may be tilted forwardly is positively limited by displacing the portion of the top cross member 22 of the yoke downwardly to provide a stop 28 engageable with a stop lug 29 formed on the head. Theportion of the top cross member 22 of the yoke [9 overlying the stop lug 20 of the head casting is displaced upwardly so that there is no interference with the desired rearward tilting. However, the

portion 28 of the top cross member of the yoke is positively engageable with the stop lug 29 to limit the forward tilting movement of the chair seat. Of course, it is to be understood that any other standard or known stop construction may be provided.

For the purpose of yieldably resisting rearward tilting of the chair seat and normally biasing the seat to a horizontal position with the stops engaged the present invention comprises an elastic body such as a rubber sleeve designated generally at 30 and combined with the head casting l3 and the yoke |9 in a novel manner which will now be described.

The rubber sleeve may be made in two or more sections and in the construction illustrated is shown as being constituted of sections 3| and 32. Each section is in the form of a frustrum of a cone. The section 32 has its large and relatively wide base 32' bearing flush against the vertical cross plate 23 of the yoke. Bosses 23' fixed to the cross plate 23 snugly fit in correspondingly formed depressions or sockets in the adjacent end of the section 32 to maintain the section 32 against transverse displacement with respect to the plate 23 in the assembly. A metal washer 34 may be interposed between the adjacent ends of the sections 3| and 32 and embossed or corrugated to prevent transverse displacement. In other words, both the bosses 23 and the corrugated washer 34 prevent buckling of the rubber sleeve assembly. The small end 3| of the rubber sleeve 3| bears against an abutment plate or disk 35 which is provided at its center with an opening of noncircular cross section, said opening being seated on the corresponding formed end portion 36' of an adjusting screw or tensioning rod 36. The plate 35 abuts the head 31 of the screw or rod 36.

The generally conical formation of the rubber sleeve arrangement insures a gradually increasing resistance to backward tilting movement, since the portions thereof of smaller cross sectional area offer less resistance to compression or deformation than the portions of larger cross sectional area. This feature of presenting a gradually increasing resistance to backward tilting movement may be materially enhanced by making the rubber sleeve section 3| of somewhat softer rubber or of rubber less resistant to deformation than the section 32. In either event it is usually desirable to provide positive means for limiting the extent to which some portions at least of the rubber sleeve assembly are deformed or expanded.

For this purpose the present invention proposes the use of a conical cup 38 shown as carried by the disk 35. It is to be understood however that the present invention is not limited to this proposed location or mounting of the cup 38. A similar cup may be mounted on the plate 23 or on the'intermediate washer 34.

In the construction illustrated the conical cup 38 is carried by the disk 35 and while this cup may be integral with the disk it is preferably threadedly interconnected therewith as indicated at 39 so that the cup 38 may be adjusted with respect to the abutment plate 35. The portion of the cup 38 threaded to the plate 35 is of circular cross section. A lock screw 48 may be used to secure the cup in any adjustment but this may be omitted if desired. The screw 36 extends through an opening 23' provided in the cross 42 of the head casting l5. A channel guide 43 is secured to the section 42 of the head casting and is provided with an opening 43' alined with the opening 4| of the casting section 42. On the bottom of this guide are bearing bosses 45 which coact with sockets 46' provided in a fulcrum bar 41. The fulcrum bar 41 has an enlarged aperture center section 49 through which the screw 36 extends. This section 48 is formed with a seat 49 against which the inner end of a hand nut 50 may be turned to increase or decrease the amount of compression applied to the sections of the rubber sleeve or block 3| and 32 and consequently to determine the resistance which these blocks present to backward tilting of the chair.

As illustrated to advantage in Figure 2 the opening through the sleeve sections 3| and 32 are tapered so that the adjusting screw 36 or the shank thereof will not engage or bear against the sleeve when the chair is tilted backwardly.

Also as shown to advantage in Figures 2 and 3 the inner wall of the cup 38 is spaced from the outer periphery of the rubber sleeve section 3| when the chair seat is horizontally positioned. The rubber sleeve section 3| is of smaller cross sectional area and may be .of somewhat softer rubber then the sleeve section 32 so that when the user of the chair first tilts backwardly thereon little resistance is presented to the movement since the sleeve 3| easily bulges or is distorted outwardly when first subjected to that additional compression. It will be understood that when the chair seat 4 is tilted backwardly the spider arms l1 and yoke l9 swing in a counter clockwise direction as viewed in Figure 2, about the pivot pin 26 and relative to the head casting l5. This swings the cross plate 23 of the yoke I9 rearwardly and downwardly. Since the screw 36 is held against longtiudinal movement by virtue of the engagement of its fulcrum bar 41 with the head casting |5 this swinging rearwardly and downwardly of the plate 23 tends to compress the rubber sleeve sections between the plate 23 and and the abutment 35.

When the chair has been tilted backwardly sufficiently to create any substantial bulge in the rubber sleev-e section 3| its outer surface will engage the cup 38 and be confined against any substantial further bulging or distortion. Any further rearward tilting movement brings into play the stiffer resilience or elasticity of the rubber sleeve section 32 so as to prevent backward tilting of the chair to an undesirable extent or without there being supplied against such tilting the resistance essential to comfort and safety.

The bulging action of the rubber sleeve sections 3| and 32 is designated by dotted lines in Figure 2 and as there indicated the bulging or extent to which the sections are distorted are of different degrees.

While the device has been shown as embodied in the so-called low fulcrum type of chair iron obviously it may be also advantageously embodied in the so-called high fulcrum type of chair iron.

While I have shown and described one construction in which the invention may be advantageously embodied, it is to be understood that this construction has been selected merely for the sake of illustration or example and that various changes in the size, shape and arrangement of the parts may be made without departing from the spirit of the invention or the scope of the subjoined claims.

The invention claimed is:

1. A chair iron comprising a spindle, a head piece fixed to said spindle, a spider having a yoke pivotally connected to said head piece, a sectional rubber sleeve having one end abutting the yoke, said sleeve having a frustro-conical form and being made up of sections of difierent degrees of elasticity, a screw extending through said sleeve and rockably interconnected with said head piece, a cup on said screw and adjustable towards said yoke and a hand nut cooperable with said screw to affect adjustment of said cup toward and away from the yoke to vary the extent to which the sections of said sleeve are compressed.

2. A chair iron comprising a spindle, a head secured to the upper end of said spindle, a spider, a yoke secured to said spider and pivotally interconnected with said head, an adjusting screw, a cup having an end plate fixed to one end of the screw and having a peripheral wall threadedly interconnected with said end plate, a tubular rubber block disposed on said screw with one end confined in said cup and its other end engaged with said yoke, the peripheral wall of the cup extending around the entire periphery of a portion of said block to limit the extent to which such portion is deformed, and a hand nut threadedly connected with the outer end of said screw and bearing against said head.

3. A chair iron comprising a spindle, a head piece fixed to said spindle, a spider having arms pivotally connected to said head piece, a sectional rubber sleeve of frustro-conical form and having its large end abutting the yoke to prevent buckling of the sleeve, a tension rod extending through said sleeve and rockably interconnected with said head piece, and an abutment on said rod engageable with the outer end of said sleeve, and a corrugated metal washer interposed between the sections of the sleeve to aid in preventing buckling thereof.

4. A chair iron comprising a spindle, a head piece fixed to said spindle, a spider having a yoke pivotally connected to said head piece, a sectional.

rubber sleeve having one end abutting the yoke, said sleeve being made up of sections of different degrees of elasticity, a screw extending through said sleeve and rockably interconnected with said head piece, a cup on said screw and adjustable towards said yoke and a hand nut cooperable with said screw to affect adjustment of said cup toward and away from the yoke to vary the extent to which the sections of said sleeve are compressed.

5. A chair iron comprising a spindle, a head piece fixed to said spindle, a spider having a yoke pivotally connected to said head piece, a rubber sleeve having portions of different degrees of elasticity and having one end abutting the yoke, a screw extending through said sleeve and rockably interconnected with the head piece, an abutment on said screw engageable with the outer end of said sleeve and adjustable toward said yoke under the influence of said screw, and a hand nut cooperable with said screw to efiect adjustment of said abutment toward and away from the yoke to vary the extent to which said sleeve is compressed, the portions of said sleeve being of difterent degrees of elasticity presenting a gradually increasing resistance to backward tilting of the spider relative to the head piece.

6. A chair iron comprising a spindle, a head piece fixed to said spindle, a spider having arms pivotally connected to said head piece, a rubber sleeve of frustro-conical form and having its large end abutting the yoke, a tension rod extending through said sleeve and rockably interconnected with said head piece, an abutment on I said rod engageable with the outer end of the sleeve, and projections fixed to the yoke and interfitted with depressions in the large end of the sleeve to maintain the same against transverse displacement.

HARRY W. BOLENS. 

